From AeroManual
Jump to: navigation, search
The "Blue Line" is VYSE

VYSE—Single-engine best rate-of-climb (VYSE)—the best rate-of-climb or minimum rate-of-sink in a light twin-engine aircraft with one engine inoperative at maximum weight at sea level. It is marked on the ASI with a blue line. VYSE is commonly referred to as “Blue Line.”